In recent years the image quality of color light-sensitive material has been significantly increased; a print of good quality can be obtained even with a small-sized format. However the storage stability of image dyes is not sufficiently satisfactory. It can be said that the fastness of each colored dye has been increased. It is, however, insufficient to increase the fastness of a particular colored dye of specific hue, because if the fastness of a particular colored dye of specific hue alone is increased, the color balance is lost and no good storage stability can be obtained. Accordingly, in order to increase the storage stability of images, it is important that all colored dyes have uniform fastness, such that even if the dyes are deteriorated during the storage, the fading in the dyes is uniform as a whole; i.e., the fading is well balanced.
In connection with cyan images, conventionally used cyan couplers (i.e., cyan-dye-forming couplers) such as a 2-acylaminophenyl cyan coupler as described in U.S. Pat. Nos. 2,367,561 and 2,423,730, and a 2,5-diacylaminophenol cyan coupler and a 1-hydroxy-2-naphthoamide cyan coupler as described in U.S. Pat. Nos. 2,369,929 and 2,772,162 are generally unsatisfactory in respect of light and/or heat fastness. As an improved cyan coupler, a phenol cyan coupler having a ureido group in the 2-position as described in U.S. Pat. Nos . 3,446,622, 3,996,253, 3,758,308, 3,880,661, 4,451,559, and Japanese patent application (OPI) No. 65134/81 (U.S. Pat. No. 4,333,999) (the term "OPI" as used herein means a "published unexamined Japanese patent application") is known. This phenol cyan coupler is greatly improved in light and heat fastness over the above conventional couplers.
In connection with the stability of magenta color image, it is generally known that a 4-equivalent 5-pyrazolone coupler which is commonly used has disadvantages in that although it is relatively high in heat fastness, its light fastness is poor, and that if the coupler remains unreacted after the processing, the unreacted coupler reacts with a magenta dye, thereby seriously reducing the heat fastness.
A high quality film has been greatly demanded in recent years. It has been found that if the 4-equivalent magenta polymer coupler as described in Japanese patent application (OPI) Nos. 28745/83 (U.S. Pat. No. 4,409,320) and 120252/83 is used, the thickness of an emulsion layer can be significantly decreased, as a result of which light-scattering is reduced and sharpness can be greatly improved. This polymer coupler, however, is not sufficiently satisfactory because it is poor in heat fastness and thus the stability of color image is unsatisfactory.